The short answer to this rather complex question is no, you cannot determine for certain whether your partner has a sexually transmitted infection, at least not without proper medical testing. This question becomes even more problematic when we take into account the fact that many STIs can stay dormant, not displaying any symptoms while still being present within the organism and being able to infect sex partners without even realising it.

While some STDs require penetrative sex in order to be transmitted to a sex partner, others are much more contagious with any genital or bodily contact being a potential risk. In this article, we will discuss some of the most common and most easily recognizable signs and symptoms of those STIs which are especially common in the UK. By reading this, you will get a clearer idea of how to recognize potential signs of an STI in your partner, but it is a far cry from having certain and reliable information on this. Once again, we are stressing that without medical testing, it is impossible to be certain whether someone is infected.

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Chlamydia is a bacterial STI and the single most common sexually transmitted disease within the UK with more than 200.000 cases being reported every year. Due to this, NHS recommends regular annual testing for anyone younger than 25 and sexually active, while advising young people to get tested every time they change a sexual partner.

Most of the people affected by chlamydia don’t exhibit any symptoms at first, and this dormant stage of the condition can continue for very long periods of time, making chlamydia that much harder to identify and diagnose.

However, even when asymptomatic, chlamydia is just as contagious and can be easily transmitted through unprotected sex. The most common symptoms include:

  • Vaginal and penile discharge
  • Vaginal bleeding after intercourse
  • Painful periods and heavy menstrual bleeding
  • Abdominal pain (in women)
  • Painful or uncomfortable urination
  • Itching sensation in the urethra (in men)
  • Testicular pain

However, it is also important to note that chlamydia can be treated very successfully with antibiotics, provided the condition is identified early. If left untreated, it can lead to other more serious complications, including infertility in both sexes and problems during pregnancy for women.


Another bacterial STI, gonorrhoea became the second most common sexually transmitted infection in the UK with 40.000 reported cases in England alone. In addition to this, a new strain of the bacteria causing this condition that is spreading across Europe seems to be resistant to antibiotics, making the treatment all the more difficult and uncertain.

This condition can be transmitted through unprotected penetrative and oral sex. However, the symptoms of the condition can be absent in majority of men and around 50% of women affected. As is the case with other STDs, gonorrhoea is contagious even when asymptomatic.

The usual symptoms are relatively similar for both sexes:



Yellow, white and sometimes green penile discharge, inflammation and swelling of the foreskin, soreness when urinating or ejaculating

Uncomfortable urination, yellow or green vaginal discharge, abdominal pain (less common), vaginal bleeding between periods, heavy menstrual periods

Despite very uncomfortable and sometimes persistent symptoms, gonorrhoea can be treated with antibiotics. In the past, a single course was enough, but with the emergence of new strains of the bacterium which are antibiotics-resilient, a combined treatment with two different types of antibiotics might be necessary in order to clear the infection.

When left untreated, this condition can cause issues with fertility in both sexes. In addition to this, further complications include problems with pregnancy and potential for miscarriage. Even if those issues are averted, baby born by affected mother can develop conjunctivitis which will need immediate antibiotic treatment in order to prevent permanent vision impairment and damage to the eyes.

Men can also develop Chordee if gonorrhoea is left untreated for long periods of time. Chordee is a condition marked by the bending of the tip of the penis which in turn makes erections painful and it might require surgery.


Syphilis is a bacterial infection that is transmitted by penetrative or oral sex, although it can lay dormant for long periods of time prior to manifesting its very severe symptoms. Although it can affect both genders, it is much more often diagnosed in men, with homosexual men being the primary risk group.

If left untreated, this condition tends to become a very serious threat to an individual’s health with potentially lethal outcome. Some of the most severe consequences of untreated syphilis include stroke, heart conditions, brain damage, loss of hearing or vision, meningitis, abnormal and tumour-like growths throughout the body.

Syphilis usually progresses in three distinct stages. The first one, also known as primary syphilis can be recognized by following symptoms:

  • One or more painless ulcers on or near the penis or vagina (can also appear on anus or mouth)
  • Swelling of the glands close to the ulcers or under the arms

Secondary syphilis produces an expanded array of symptoms:

  • General malaise
  • Headache
  • Sore throat
  • Skin rash
  • Appearance of various acute health problems

Finally, the third and final stage of syphilis involves two distinct sub-stages – latent syphilis which is marked by a sudden disappearance of any symptoms and tertiary syphilis which is marked by the exacerbation of the mentioned symptoms and severe health complications that were mentioned above.

Syphilis can be successfully treated with antibiotics in its early stages and even in the final one, although it might require intravenous administration of antibiotics. However, curing the illness in the later stage will not automatically treat all the complications that arose as a result of a long-term infection.


Probably the best-known STI, the human immunodeficiency virus (also known as HIV) can be transmitted through unprotected vaginal or anal sex, as well as through infected blood. As of now, there is no known cure for this very serious condition, although there are some promising leads which seem to imply that we might see the development of a successful and efficient treatment in the near future.

Throughout the past years, this condition was the cause of the lethal acquired immune deficiency syndrome (also known as AIDS). However, with the development of modern medicine, it is now possible for people infected by HIV to live otherwise healthy and fulfilled lives, provided they take proper treatment and make certain life style changes required in order to manage their condition.

As is evident from the name, HIV compromises the ability of the body’s immune system to combat various infections and diseases, making even the most common illnesses very dangerous. When left untreated, it will progress to AIDS when conditions such as pneumonia and tuberculosis become clear and present dangers that can hardly be averted.

As is the case with many other STDs, people with HIV can also live normally for several years without noticing any of the symptoms. However, even in this asymptomatic stage of the disease, they can still infect sexual partners, with the risk factor being the same as in people with developed symptoms.

HIV affects both genders in roughly the same way and with the same prevalence. According to NHS estimates, some 6.000 people are diagnosed annually in the UK with additional 100.000 living with the condition. Some scientists estimate that more than a quarter of those affected by HIV globally live with the condition without even knowing it.

Some of the early symptoms of HIV include:

  • Symptoms of influenza or common cold
  • General malaise
  • Headache
  • Fatigue
  • Sore throat
  • Fever
  • Joint pain
  • Muscle pain
  • Mouth ulcers

After these initial symptoms, the condition can enter a long period of dormancy which can last for years at the time. During this period, the virus will still be present, but will not manifest any symptoms whatsoever. However, throughout this period, the immune system will get weaker and weaker up until the point where it stops being able to fight of common infections. This will be followed by weight loss, acute diarrhoea, and increasingly chronic nature of otherwise curable and trivial medical conditions.

Genital warts

As a rather common viral STI, genital warts are ranked as the second most prevalent sexually transmitted infection in the UK. Caused by Human papillomavirus, often abbreviated to HPV, this condition is moderately contagious as it is transmitted through skin-to-skin contact. The symptoms of genital warts are relatively easy to recognize, with the tell-tale sign being the formation of clusters of small growths with the appearance of cauliflower in the genital area.

In affected women, the growths usually appear inside the vagina, on the vulva, cervix, upper thighs or anus, while for men, the most common locations include penis, anus, urethra, and scrotum. However, these symptoms do not necessarily occur as soon as one contracts the virus – on the contrary, genital warps can lay dormant for several weeks or even months before the symptoms manifest.

Genital herpes (HSV-2)

It is dangerously easy not to notice a herpes outbreak, so this condition is often transmitted without knowing it. The main symptoms include:

  • Sore and itchy blisters on or near the genital, thighs and bottom
  • General malaise
  • Symptoms of influenza

What makes herpes even more contagious is the fact that it can be spread not just through penetrative sex, but also through any genital contact. In addition, this infection can also spread to the mouth via kissing after oral sex.

It is important to note that once when this virus enters the body, it cannot get completely cured. However, with proper treatment, it can be successfully managed, so that flare-ups of symptoms remain rare if not completely absent.

Trichomoniasis (TV)

Trichomoniasis, also known as TV is a sexually transmitted disease caused by a parasitic called Trichomonas vaginalis. The symptoms of TV are often mistaken for other conditions as this parasite affects the genitals and urethra and in rare cases prostate gland and head of the penis.

Symptoms of TV are gender-specific, with women experiencing the following symptoms:

  • Irregular vaginal discharge (changes in consistency, colour or smell)
  • Pain and inflammation around the vagina
  • Itching in the upper thighs
  • Painful urination
  • Painful sexual intercourse

Men affected usually report symptoms such as:

  • Infection of the urethra
  • Infection of the foreskin
  • Inflammation of the prostate gland
  • Painful urination
  • Painful ejaculation
  • Frequent urination
  • Thin white discharge and soreness around the head of the penis (balanitis)

STI testing

For a sexually active individual, the only 100% certain way to ensure that he or she is completely free of any STIs is to get tested regularly. This can be done in numerous ways. The more conventional routes include visiting GUM clinics (sometimes called STI clinics) and getting a test there. GUM clinics are completely confidential and discreet. Aside from testing, you can often get some useful advice there, or also get access to free contraceptives. However, keep in mind that the doctor will probably make an inquiry regarding your recent sexual history – while this is a very uncomfortable topic to talk about with a doctor, it is very important to be honest and open about it so the risks are properly assessed.

However, if you aren’t looking forward to sharing these rather intimate and personal details with someone and you really want to avoid visiting a GUM, a rather convenient and reliable alternative can be an STI home test. In this way, you will take samples (urine sample and non-invasive vaginal swab for women) by yourself in your home and then post them to a certified laboratory which will inform you about the results without the need for any face-to-face meeting or contact.